Modeling and Analysis of Geometrically Complex Corrosion Damage

In order to validate computational models of corrosion, quantitative assessment of corrosion damage is needed. This thesis describes work addressing these two issues: (a) develop and exercise an open-source algorithm to analyze corrosion damage revealed in cross-sections of corroded specimens, and (b) develop and exercise a computational framework for calculation of potential and current distributions on complex geometrical structures involving galvanic couples under thin electrolyte layer conditions.
A digital image processing method has been developed using MATLAB to perform several tasks that researchers could find useful on cross sectional images. This method takes a RGB image and outputs valuable data on the depth profile. This information can be presented as an area ratio, a depth profile, or a histogram of damage occurred. This method has shown to be accurate, adaptable, and efficient compared to other methods.
A geometrically complex model was constructed in COMSOLTM to investigate the effects of sample geometry, including spacing between fasteners and their location relative to the edges of the sample, as well as water layer thickness. This complex model is based on the NAVAIR galvanic corrosion assembly and utilizes the secondary current distribution framework in COMSOLTM to simulate various scenarios using real-life experimental data for the boundary conditions. Galvanic interaction between the fasteners was observed and the intensity of attack was most severe at the edge of the hole.